人在旅途--JAIN SIP instantmessaging学习

人在旅途发表于 2006/1/17 15:15:19

学习目的:通过阅读源程序,了解如何使用JAVA的JAIN包来制作SIP客户端程序(IM). 学习笔记: Class 说明 InstantMessagingGUI 启动类,负责显示主画面,读如初始化文件,初始化个变量,启动和停止SIPListener. IMUserAgent 实现SIPListener.借口,负责SIPStack和SIPProvider等SIP通信类的生成和初始化,SIPListener的登记和注销,响应各种到达的事件(SIP消息). ListenerInstantMessaging 负责响应主画面的各种UI操作,如Sign in,OFFLINE,IM... IMMessageProcessing 负责IM聊天中的消息发送和接受,其中有DIALOG概念 AuthenticationDialog 让用户输入ID和密码 AuthenticationProcess 负责提供从认证文件来的ID和密码信息,产生认证要求SIP消息的回映SIP消息的头 BuddyList 负责主画面中BuddyList的操作(加,减,信息...)和所对应的认证文件相关操作(读如,保存) BuddyTag BuddyList中的一项 ChatFrame IM画面 ChatSession 负责一个IM画面的操作,各种IM信息管理,收发操作(信息显示,SIP发信...),IM的SIP对话管理 ChatSessionManager 多个ChatSession管理 AlertInstantMessaging 显示错误信息 ConfigurationFrame 初始化信息管理画面 RemoteSipURLFrame 让用户输入IM的对方地址 presence下*Processing 负责各种SIP消息的接受分析和回应 IMRegisterProcessing 负责REGISTER和UNREGISTER消息,成功后会调用IMSubscribeProcessing和IMNotifyProcessing发送附加消息注:gov.nist.javax.sip.Utils被使用,但它在API文档中不存在. 1.REGISTER(sign in)消息消息行说明 REGISTER sip:nist.gov:4000 SIP/2.0 请求方法 URI SIP版本号 Call-ID: nist-sip-im-register-callId1 主机本地表示 CSeq: 1 REGISTER 同一CALLID中的序数请求方法 From: <sip:deruelle@nist.gov>;tag=924 FROM(用户) 标记(区别共享同一IP地址相同CALLID的请求) To: <sip:deruelle@nist.gov> TO(用户) Via: SIP/2.0/UDP 127.0.0.1:4010;branch=z9hG4bK973d37d8ff9de1a0e2a50e5ff70f82e7 发送协议发送方分支参数(用于代理服务器并行分发请求时标记个分支) Max-Forwards: 10 Contact: <sip:127.0.0.1:4010;transport=udp> 给出以后需要时的直接通讯地址 Allow: INVITE, SUBSCRIBE, NOTIFY, MESSAGE, INFO, PUBLISH Content-Length: 0 2.REGISTER(sign in)消息的响应消息行说明 SIP/2.0 200 OK SIP版本号状态码状态说明 Call-ID: nist-sip-im-register-callId1 (同请求) CSeq: 1 REGISTER (同请求) From: <sip:deruelle@nist.gov>;tag=924 FROM(用户) 标记(区别共享同一IP地址相同CALLID的请求) To: <sip:deruelle@nist.gov> TO(用户) Via: SIP/2.0/UDP 127.0.0.1:4010;branch=z9hG4bK973d37d8ff9de1a0e2a50e5ff70f82e7 发送协议发送方分支参数(用于代理服务器并行分发请求时标记个分支) Max-Forwards: 10 Contact: <sip:127.0.0.1:4010;transport=udp>;expires=3600 直接通讯地址(同请求) REGISTER有效时间 Content-Length: 0 3.REGISTER(sign out)消息基本和REGISTER(sign in)消息一样,只是在以下两个方面不同: 3.1<TO>头部字段和<FROM>头部字段一样加了个标记项. 3.2<Allow>头部字段没有了,被一个<Expires: 0>头部字段所代替了. 4.REGISTER(sign out)消息的响应和REGISTER(sign out)消息一样有了相应的变化(标记项和<Expires: 0>头部字段). 5.Subscribe和Unsubscribe消息(IM的消息)在增加一个Contact(联系人)后要向该联系人发送Subscribe消息,该联系人收到该消息后可以认证发送者后作出不同响应.在删除一个Contact(联系人)后要向该联系人发送Unsubscribe消息,该消息后和Subscribe基本相同,expiresHeader为0或空的是Unsubscribe消息,有大于0数据的是Subscribe消息.这两个消息和其他SIP消息一样都靠SIPProxy转送.如果消息的接受一方没有Register(在线),SIPProxy会代理没有在线一方响应.在用户SignIn(发送REGISTER消息)后会自动向所有BUDDYLIST中的用户(联系人)发送SUBSCRIBE消息.同样在用户SIGNOUT(发送UNREGISTER消息)后也应该向所有BUDDYLIST中的用户(联系人)发送UNSUBSCRIBE消息.Subscribe消息的发送和响应如下:发送者先检查看和联系人是否已经有DIALOG了,如果已经有了那么fromHeader和toHeader等参数就从DIALOG中取并用DIALOG发送消息,不然就自己产生参数(fromHeader中有新TAG数据而toHeader中没有TAG数据)并用新的TRANSACTION发送.联系人方收到该消息后,立即返回OK响应消息.随后认证发送者,如果可以接受发送者,就向presenceManager中追加或更新发送者所代表的Subscriber(包括名字,响应消息和DIALOG),并把自己状态通过Notify消息发给发送者(通过SIPPROXY);如果认证结果为不可接受,就通过Notify消息(状态为NULL)通知发送者.发送者收到响应消息后,就从消息中取得新的DIALOG并往presenceManager中追加或更新发送者所代表的Presentity(包括名字,响应消息和DIALOG).再往buddyList中追加该联系人的情报.Unsubscribe消息的发送和响应如下:消息的发送和Subscribe消息的发送一样只是expiresHeader为0.联系人方收到该消息后,就检查DIALOG情报,如果消息发自以前发送过Subscribe消息的用户(有DIALOG),就返回OK响应,并向发送方发送状态为NULL的NODIFY消息;如果消息发自以前没有发送过Subscribe消息的用户(没有DIALOG),就返回CALL_OR_TRANSACTION_DOES_NOT_EXIST响应.发送者收到响应消息后,不做任何处理.

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Best Places To Retire

软件技术

Kids Timberland Boots(游客)发表评论于2010/4/1 13:45:47

Go ahead, dream a little. Retirement may be years, or even decades, away. But that doesn't mean you can't think about it--and where you might spend your golden years. For some, it's the stillness of a cool morning while fishing on a lake. For others, it's the feel of warm sand between the toes as the surf rushes in. For still others, it's the hurly-burly of city life with bookstores, restaurants, theaters, and museums.To help you get started on the process of picking a favorite place, U.S. News put together a list of about 2,000 American places with a population above 15,000. Yes, some people prefer even fewer neighbors, and rural life has its charms. But often those charms come with limited access to top medical care or not enough job options for those retirees who may want or need additional income.From that first cut Kids Timberland Boots of 2,000, we winnowed it down to a little over 1,000 places, using criteria that included cost of living, climate, crime rate, access to healthcare, educational opportunities, and cultural and recreational amenities. To whet your appetite, we selected 10 editors' picks (from Bozeman, Mont., to Venice, Fla.), which you'll find profiled in the following pages. There's a big-city splurge, San Francisco, with world-class culture and dining, breathtaking views, and, yes, housing prices to match. But there are also heartland ...

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